The ABC-Pyramid Atmospheric Research Observatory in Himalaya for aerosol, ozone and halocarbon measurements

In this work we present the new ABC-Pyramid Atmospheric Research Observatory (Nepal, 27.95 N, 86.82 E) located in the Himalayas, specifically in the Khumbu valley at 5079 m a.s.l. This measurement station has been set-up with the aim of investigating natural and human-induced environmental changes at different scales (local, regional and global). After an accurate instrumental set-up at ISAC-CNR in Bologna (Italy) in autumn 2005, the ABC-Pyramid Observatory for aerosol (physical, chemical and optical properties) and trace gas measurements (ozone and climate altering halocarbons) was installed in the high Khumbu valley in February 2006. Since March 2006, continuous measurements of aerosol particles (optical and physical properties), ozone (O3) and meteorological parameters as well as weekly samplings of particulate matter (for chemical analyses) and grab air samples for the determination of 27 halocarbons, have been carried out. These measurements provide data on the typical atmospheric composition of the Himalayan area between India and China and make investigations of the principal differences and similarities between the monsoon and pre-monsoon seasons possible. The study is carried out within the framework of the Ev-K2-CNR "SHARE-Asia" (Stations at High Altitude for Research on the Environment in Asia) and UNEP-"ABC" (Atmospheric Brown Clouds) projects. With the name of "Nepal Climate Observatory-Pyramid" the station is now part of the Observatory program of the ABC project.

[Multiple sclerosis and Leber's hereditary optic neuropathy mitochondrial DNA mutations]

Multiple sclerosis (MS) has long been known to be associated with Leber's hereditary optic neuropathy (LHON), a disease caused by mitochondrial DNA (mtDNA) mutations. We have investigated the possible involvement of LHON mtDNA point mutations in MS. The study covered a group of 75 unrelated Caucasian patients, with the relapse-remitting or primary progressive form of MS, and a control group of 75 volunteers (matched for age, gender and ethnic origin). Mitochondrial DNA from each subject was examined for 4 primary LHON mutations (at nucleotide positions 3460, 4160, 11778 and 14484) and 7 secondary LHON mutations (at nucleotide positions 4216, 4917, 5244, 7444, 13708, 15257 and 15812) by means of restriction site polymorphism and sequencing techniques. None of the primary LHON mutations were detected in the MS patients or in the controls, whereas the proportion of individuals with secondary LHON mutations was identical (27 p. cent) in the two groups. A combination of 2 or 3 homoplasmic mutations, defining mtDNA haplogroups, was found in the majority of cases. Haplogroups J, T and X were not particularly associated with MS. The frequency of the 13708 mutation alone (haplogroup X), or associated with the 4216 mutation (haplogroup J), was somewhat higher (p=0.059) in the subgroup of MS patients with optic neuritis (ON). ON was the initial symptom in all but one of the patients with haplogroups J or X. No other correlation was found between MS phenotypes and mtDNA genotypes. Our observations confirm previous reports that neither primary nor secondary LHON mutations are involved in the development of MS. However, MS patients with haplogroups J or X appear to have a moderately higher risk of developing optic neuritis. Thus, a specific mtDNA background may be a predisposing genetic factor for optic nerve damage in MS patients.

Ischaemic myelopathy following aortic surgery or traumatic laceration of the aorta

Paraplegia is one of the major complications following repair of aortic aneurysms or congenital malformations and from trauma of the aorta. In a series of 12 surviving patients we describe the clinical features as well as the evolution and pathophysiology of ischaemic lesions of the spinal cord. The clinical characteristics: loss of tendon reflexes, preservation of light touch sensation and bladder function, and the special topography of pin prick impairment, suggest involvement of the central grey matter. This lesion of the grey matter is incomplete in most of the patients and tends to extend for 2-10 segments. In some cases it can extend downward to the conus resulting in complete flaccid paraplegia. On follow-up we have observed limited improvement in most cases. No patient has recovered fully. Except in cases of traumatic laceration, where symptoms existed before surgery, paraplegia followed surgical repair in all other cases. Ischaemia can be related to the duration and the site of crossclamping of the aorta. Clamping above the left subclavian artery and/or a ligation of the intercostal arteries without previous visualisation of the spinal cord arteries can be dangerous. Other factors such as the phenomena of revascularisation and the presence of free radicals are discussed. These could explain delayed postischaemic spinal cord hypoperfusion.

Reducing the number of rabbits in the Draize eye irritancy test: a statistical analysis of 155 studies conducted over 6 years

The Draize eye irritancy test in rabbits has been the focus of recent efforts to reduce the use of live animals in toxicity testing. A suitable alternative is not yet available; therefore, we studied the adequacy of reducing the number of rabbits used per test. Data generated from 6-rabbit eye irritation tests of 155 various materials were used to determine the ability of irritation scores from all possible combinations of 5-, 4-, 3-, or 2-rabbit subsets to predict the Draize score derived from six rabbits. There are 930, 2325, 3100, and 2325 possible combinations of 155 studies for the 5-, 4-, 3-, and 2-rabbit subsets, respectively. We classify materials using a four-level adjectival rating system based on (among other factors) the Draize score. Comparisons indicated that 5-, 4-, 3-, and 2-rabbit scores were in 98, 96, 94, and 91% agreement, respectively, with the classification assigned on the basis of the 6-rabbit score. The correlation coefficients for randomly selected subsets of 5-, 4-, 3-, and 2-rabbit scores versus the Draize score for six rabbits were 0.998, 0.996, 0.992, and 0.984, respectively. This study confirms the findings of an earlier report by De Sousa et al. (1984), and indicates that a high level of accuracy can be obtained with reduced numbers of rabbits per test.

A model of immunologic lung injury induced by trimellitic anhydride inhalation: antibody response

We studied lung injury induced in Sprague-Dawley rats by trimellitic anhydride (TMA) inhalation. Groups of 40 male and 20 female rats were exposed to TMA by inhalation at target concentrations of 0, 10, 30, 100, and 300 micrograms/m3, 6 hours per day, 5 days per week, for 2 weeks. Rats in each exposure group were sacrificed after 10 exposures or rested for 12 days and either sacrificed or received a 6-hour TMA challenge at their initial exposure levels and sacrificed at 24 hours. At each sacrifice, serum antibody to radiolabeled trimellityl rat serum albumin (RSA-TM) was measured by an ammonium sulfate technique, and lung pathology was determined. After 10 days of exposure, external hemorrhagic lung foci were directly related to the exposure concentration of TMA. Serum antibody binding of RSA-TM correlated with exposure concentration, hemorrhagic lung foci, and lung weight. There was healing of lung lesions 12 days after exposure with a return of lung lesions only 18 hours after the 6-hour inhalation challenge. A correlation between serum antibody to RSA-TM, hemorrhagic foci, and lung weight existed after challenge. This model clarifies two clinical entities observed in exposed workers, the late respiratory systemic and the pulmonary disease-anemia syndromes.

The pathologic and immunologic response to inhaled trimellitic anhydride in rats

Trimellitic anhydride (TMA) is a chemical intermediate used in the paint and plastics industry. Inhalation of TMA can induce four types of syndromes in TMA workers; three are immunologically based whereas the fourth, an irritant syndrome, is nonimmunologic. To evaluate the potential inhalation hazard of TMA under controlled conditions, Sprague-Dawley rats were exposed 6 hr/day via inhalation to target concentrations of 0, 10, 30, 100, and 300 micrograms/m3 for varying durations. Two sets of rats received either 5 or 10 exposures and were terminated. A third set received 10 exposures, and was held 12 days and terminated. A fourth set received 10 exposures, and was held 12 days, challenged with a single 6-hr exposure, and terminated. A fifth set received 10 exposures, and was held 12 weeks and terminated. There were no effects after 5 exposures; however, after 10 exposures the following parameters were increased in a concentration-related manner: absolute and relative lung weights, external hemorrhagic lung foci, alveolar macrophage accumulation, alveolar hemorrhage, pneumonitis, and lung and mediastinal lymph node nonspecific IgG and complement (C3). The rats exposed and rested 12 days were nearly recovered from these effects; however, rats rested 12 days and subsequently challenged exhibited lesions similar to those seen immediately following exposure. Exposed rats rested 12 weeks were completely normal in all of the above parameters. The timing and nature of the lung lesions, along with the presence of lung IgG and complement, are consistent with some of the known aspects of TMA-induced lesions in humans, and are reflective of results obtained from other hypersensitivity pneumonitis models.

[Control of hypertension and blood lactate during exercise. Comparison of central antihypertensive agents with the cardio-selective beta blockers metoprolol and atenolol]

To assess whether betablockers (BB) would better control blood pressure than central antihypertensive drugs (CAD) clonidine or alpha methyldopa in hypertensive patients during exercise, comparable triangular ergometric bicycle exercises were performed by the same patients while their hypertension had been controlled at rest either with CAD or BB. Blood pressure, heart rate and blood lactate before and during exercise were compared in II patients treated with metoprolol and CAD, and in 12 other patients treated with atenolol and CAD. Systolic and diastolic blood pressure on exercise were significantly lower with BB than with CAD. Heart rate and rate-pressure product were always lower with BB than with CAD. Blood lactate increase was greater with BB than with CAD. The work capacity was greater with atenolol than with CAD, but comparable between metoprolol and CAD.